[bug] gemonlinedb tests fail to build with xdaq15

[jsturdy]

Brief summary of issue

During testing for #311 one of the tests for gemonlinedb failed to compile (gcc 8.3.1 from devtoolset-8)

Types of issue

• Bug report (report an issue with the code)

Expected Behavior

Tests should build and succeed.

Current Behavior

One test fails to compile wit the following error:

g++  -g -O2 -Wall -fPIC -fno-omit-frame-pointer -DGIT_VERSION=\"v1.1.0-rc-100-g3ca28dfb-dirty\" -DGEMDEVELOPER=\"sturdy\" -DXDAQ15 -std=c++2a -std=gnu++2a -I/usr/include/python2.7   -DOS_VERSION_CODE=199168 -Dx86_64_centos7 -Dlinux -DLITTLE_ENDIAN__ -I/home/sturdy/src/sw/cmsgemos/gemonlinedb/include/linux -I/home/sturdy/src/sw/cmsgemos/gemonlinedb/include -I/opt/xdaq/include -I/home/sturdy/src/sw/cmsgemos/gemonlinedb/include -I/home/sturdy/src/sw/cmsgemos/gembase/include -I/home/sturdy/src/sw/cmsgemos/gemutils/include -I/home/sturdy/src/sw/cmsgemos/x86_64_centos7/include -I/home/sturdy/src/sw/cmsgemos/x86_64_centos7/include/linux -I/opt/xdaq/include -I/opt/xdaq/include/linux -c -o /home/sturdy/src/sw/cmsgemos/gemonlinedb/test/linux/x86_64_centos7/test/testConfigurationManager.o test/testConfigurationManager.cc
In file included from test/testConfigurationManager.cc:1:
/opt/rh/devtoolset-8/root/usr/include/c++/8/atomic: In instantiation of ‘struct std::atomic<std::__exception_ptr::exception_ptr>’:
test/testConfigurationManager.cc:54:41:   required from here
/opt/rh/devtoolset-8/root/usr/include/c++/8/atomic:187:21: error: static assertion failed: std::atomic requires a trivially copyable type
       static_assert(__is_trivially_copyable(_Tp),
                     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~

Steps to Reproduce (for bugs)

1. Check out the code in Migrate to xdaq15 and refactor gemhardware #311
2. Run make gemonlinedb
3. Run make gemonlinedb.tests

Context

Working to migrate to newer compiler and xdaq15

Your Environment

• Version used: commits in Migrate to xdaq15 and refactor gemhardware #311
• Shell used: zsh
• Compiler used: gcc 8.3.1